Data from: Bayesian inference of a complex invasion history revealed by nuclear and chloroplast genetic diversity in the colonizing plant, Silene latifolia

Species invading new ranges are subject to a series of demographic events that can strongly shape genetic diversity. Describing this demographic history is important for understanding where invasive species come from and how they spread, and is critical to testing hypotheses of post-invasion adaptation. Here, we analyze nuclear and chloroplast genetic diversity to study the invasion history of the widespread colonizing weed, Silene latifolia (Caryophyllaceae). Bayesian clustering and PCA revealed strong population structure in the native range of Europe and although genotypes from multiple native sources were present in the introduced range of North America, the spatial distribution of genetic variance was dramatically reorganized. Using approximate Bayesian computation (ABC), we compared support for different invasion scenarios, including the number and size of independent introduction events and the amount of admixture occurring between sources of introduced genotypes. Our results supported independent introductions into eastern and western North America, with the latter forming a bridgehead for a secondary invasion into the Great Lakes region of central North America. Despite small estimated founder population sizes, the duration of the demographic bottleneck after the initial introduction appeared extremely short-lived. This pattern of repeated colonization and rapid expansion has effectively eroded the strong population structure and cyto-nuclear associations present in Europe, but has retained overall high genetic diversity since invasion. Our results highlight the flexibility of the ABC approach for constructing a narrative of the demographic history of species invasions, and provide baseline for future studies of evolutionary changes in introduced S. latifolia populations.

入侵新分布区的物种会经历一系列可强烈塑造其遗传多样性的种群动态事件。阐明此类种群动态历史，对于解析入侵物种的起源与扩散路径至关重要，同时也是检验入侵后适应假说的核心前提。本研究针对广布入侵杂草麦瓶草（Silene latifolia，石竹科Caryophyllaceae）的入侵历史展开分析，对其核基因组与叶绿体基因组遗传多样性进行了检测。贝叶斯聚类与主成分分析（Principal Component Analysis, PCA）结果显示，该物种在欧洲原生分布区存在显著的种群结构；尽管北美入侵分布区存在来自多个原生来源的基因型，但遗传变异的空间分布已发生显著重构。本研究借助近似贝叶斯计算（Approximate Bayesian Computation, ABC），对不同入侵情景的支持度进行了比较，包括独立引入事件的数量与规模、入侵基因型来源间的遗传混合程度。研究结果支持北美东西部存在独立引入事件的假说，其中西部入侵种群可作为二次入侵的桥头堡，进一步扩散至北美中部五大湖区域。尽管估算得到的奠基者种群规模较小，但初始引入后的种群瓶颈持续时长极短。这种反复定殖与快速扩张的模式，有效消除了欧洲原生种群中显著的种群结构与核质关联，但入侵后整体遗传多样性仍维持在较高水平。本研究凸显了近似贝叶斯计算方法在构建物种入侵种群动态历史叙事中的灵活性，同时为后续针对入侵麦瓶草种群演化变化的研究提供了基准参照。